18)The antifluorite structure is derived from a fluorite structure by a)Heating the fluorite crystal latticeb)Subjecting the fluorite structure to high pressurec)Interchanging the positions of the positive and negative ions in the latticed)None of these

19)An example of a fluorite structure isa)NaF b)c)d)

20) An example of a non-stoichiometric compound isa)NaF b)c)d)ZnS

21) Which one of the following is a ferrite?a)b)c)d)

22)Which of the following adopts a normal spinel structure?a)CsCIb)c)FeOd)

34)In stoichiometric defects, the ratio of positive and negative ions as indicated by chemical formula of the compound:a)decreasesb)increasesc)remains the samed)cannot be predicted

35)In the Schottky defecta)cations are missing from the lattice sites and occupy the interstitial sitesb)an equal number of cations and anions are missingc)Anions are missing and electrons are present in their placed)an equal number of extra cations and electrons are present in the interstitial sites

36)As a result of the Schottky defect,a)there is no effect on the densityb)the density of the crystal increasesc)the density of the crystal decreasesd)any of the above three can happen

37)A Schottky defect is observed in the crystal ofa)NaCIb)TICIc)AgCId)

38)Choose the correct statements out of I,II and IIII) A Schottky defect lowers the density II) A Frenkel defect increases the dielectric constant of the crystals III) Stoichiometric defects make the crystals good electrical conductorsa)I and II onlyb)II and III onlyc)III and I onlyd)I,II and III

39)Which of these shows the Frenkel defect ?I) AgBr II) Agl III) Zna)I and II onlyb)II and III onlyc)I and III onlyd)All three

40)Frenkel defect is found in crystals in which the radius ratio is:a)lowb)1.3c)1.5d)slightly less than unity

41)As a result of the Frenkel defect,a)there is no effect on the densityb)there is no effect on the conductivityc)there is no effect on the dielectric constantd)there is no effect on all the three above

43)Which of the following statements I Â– II about F-centres is/are correct ? I) Electrons are held in the voids of crystals II)F-centres impart colour to the crystal III) The conductivity of the crystal increases due to F-centresa)I and II onlyb)II and III onlyc)I and III onlyd)All three

46)The doping of silicon with P or AI increases the conductivity. The difference in the two cases is thata)P is non-metal whereas AI is a metalb)P is a poor conductor while AI is a conductorc)P gives rise to extra electrons while AI gives rise to holesd)P gives rise to holes while AI gives rise to extra electrons

47)ZnO is white when cold and yellow when heated. This is due to the development ofa)Frenkel defectsb)Schottky defectsc)Metal excess defectsd)Metal deficiency defects

48)When an NaCI crystal is doped with , the nature of the defect produced is a)interstitial defectb)Schottky defectc)Frenkel defectd)none of these

49)Which of the following statements is incorrect? a)CsCI crystal shows a Schottky defectb)Crystals with F-centres are coloured and paramagneticc)The photo sensitivity of AgBr is due to the presence of a Frenkel defect in its crystalsd)None of these

50)Solid NaCI is a bad conductor of electricity sincea)In solid NaCI there are no ionsb)Solid NaCI is covalentc)In solid NaCI ionic mobility is lowd)In solid NaCI there are no electrons

51)Which one of the following statements is wrong?a)The conductivity of metals decreases with an increase in temperatureb)The conductivity of semiconductors increases with an increase in temperaturec)There are no superconductors at room temperatured)Ionic solids conduct electricity due to the presence of ions

52)Which substance will conduct current in the solid state?a)Diamondb)Graphitec)Iodined)Sodium chloride

53)A metal has bcc structure and the edge length of its unit cell is . The volume of the unit cell in will bea)b)c)d)

54)An oxide of a transition metal that has a conductivity as well as an appearance like that of copper isa)b)c)d)

55)The oxide that is an insulator is a)VOb)CoOc)d)

56)Molten sodium chloride conducts electricity due to the presence of a)free electronsb)free ionsc)free moleculesd)atoms of sodium and chlorine

57)Silicon is a a)Conductorb)Semiconductorc)Nonconductord)Metal complex

58)Which of the following oxides of chlorine is paramagnetic?a)b)c)d)

59)Select the paramagnetic ion:a)b)c)d)

60)Which of the following species is not paramagnetic?a)NOb)c)d)None of the above

61)Which of the following is not diamagnetic?a)b)c)d)All are diamagnetic

62)Ferromagnetic substances have aa)zero magnetic momentb)small magnetic momentc)Large magnetic momentd)Magnetic moment ranging from small to large

79)Select the correct statement from the following: a)A cubic close packed structure has eight tetrahedral and six octahedral intersticesb)Graphite has a three dimensional crystal latticec)Diamond has a two dimensional crystal latticed)font face=”Arial”>The coordination number of a body centred cubic lattice is eight.

87)Which one of the following is a two dimensional covalent solid?a)graphiteb)quartzc)carborundumd)pure germanium

88)When n- and p-type semiconductors are allowed to come into contacta)Some electrons will flow from n to pb)Some electrons will flow from p to nc)The impurity element will flow from n to pd)The impurity element will flow from p to n

89)In which of the following substances is the carbon atom arranged in a tetrahedral structure?a)Diamondb)Benzenec)Graphited)Carbon black

90)Of the values required to calculate a lattice energy using the Born-Haber cycle, the one that is most difficult to measure is a)The electron affinity of the non-metalb)The heat of formation of gaseous atoms of the non-metalc)The ionisation energy of the metald)The heat of sublimation of metal

98)A pressure cooker reduces cooking time becausea)the heat is more easily distributedb)the higher pressure tenderizes the foodc)the boiling point of the water inside is elevatedd)a large flame is used

99)How many ions are there around the ion in NaCI crystal? a)3b)4c)6d)8

100)The liquid is in equilibrium with its vapours at its boiling point. On the average, the molecules in the two phases have equala)Potential energyb)Total energyc)Kinetic energyd)Intermolecular forces